1. Field of the Invention
The present invention relates to an adhesion promoter for organopolysiloxane compositions which are cured by radiation, such as by an electron beam and ultraviolet radiation.
2. Prior Art
While heating is primarily used in the prior art to cure organopolysiloxane compositions, this approach does require high temperatures and long curing times. Accordingly, the last several years have been witness to research into compositions and methods by which curing can be conducted at lower temperatures and in shorter times. This research has resulted in the appearance of organopolysiloxane compositions which are cured by exposure to radiation such as an electron beam, ultraviolet radiation, etc. Such compositions are exemplified by compositions which are obtained by mixing a photosensitizer into the mixture of a mercapto group-containing organopolysiloxane and a vinyl group-containing organopolysiloxane as described in Canadian Patent No. 1,019,693 issued to Gant Oct. 25. 1977. and by compositions composed of photosensitizer plus organopolysiloxane having acryloxy or methacryloxy groups as described in Japanese Patent Publication Number 53-2911[2.911/78].
3. Problem to Be Solved by the Invention
However, these organopolysiloxane compositions do not adhere well to the surfaces of various substrates, such as plastics, rubbers, metals etc., after curing, and as a consequence are easily removed by rubbing with the finger, etc.
The present inventors carried out vigorous research with a view to the elimination of the above problem and this invention was developed as a consequence.
The object of the present invention is to provide an adhesion promoter which, when blended into radiation-curable organopolysiloxane or a composition thereof, will generate a substantial increase in adhesion for various substrates.
4. Means Solving the Problem and Functions Thereof
The present invention comprises an adhesion promoter for radiation-curable organopolysiloxane, or a composition thereof, wherein said adhesion promoter consists of silane or polysiloxane having in each molecule at least one organic group possessing aliphatic unsaturation and at least one organic group possessing the amino group, or of silane or polysiloxane having in each molecule at least one organic group possessing both aliphatic unsaturation and the amino group.